Vibrational and structural properties in the dihydrate sodium tungstate and in the dihydrate sodium molybdate crystals

2013 ◽  
Vol 1033 ◽  
pp. 154-161 ◽  
Author(s):  
G.D. Saraiva ◽  
C. Luz-Lima ◽  
P.T.C. Freire ◽  
A.J. Ramiro de Castro ◽  
G.P. de Sousa ◽  
...  
Keyword(s):  
Structural Properties ◽  
Sodium Tungstate ◽  
Sodium Molybdate

Oxoanions stimulate in vitro ovulation and signal transduction pathways in goldfish (Carassius auratus) follicles

1992 ◽  
Vol 263 (5) ◽  
pp. E943-E949 ◽  
Author(s):  
S. Y. Hsu ◽  
F. W. Goetz
Keyword(s):  
Signal Transduction ◽  
Carassius Auratus ◽  
Sodium Tungstate ◽  
Sodium Molybdate ◽  
Vanadyl Sulfate ◽  
Signal Transduction Pathways ◽  
Sodium Selenate ◽  
Sodium Chromate ◽  
Goldfish Carassius Auratus

The present study investigated the effects of a number of oxoanion compounds on in vitro ovulation of goldfish follicles and ovarian second messenger activities. Significant levels of ovulation were induced by 0.1 mM sodium chromate, 0.1 mM sodium metavanadate, 10 mM sodium molybdate, 0.1 mM sodium orthovanadate, 5 mM sodium selenate, 0.5 mM sodium tungstate, and 0.1 mM vanadyl sulfate. At levels that significantly stimulated ovulation, metavanadate, molybdate, orthovanadate, tungstate, and vanadyl sulfate also stimulated follicular phosphatidylinositol cycling and inhibited ovarian alkaline phosphatase activity. Moreover, the ovulation induced by these oxoanions was not inhibited by indomethacin (10 micrograms/ml), while ovulation induced by selenate and chromate was. In contrast, only vanadium-containing compounds significantly stimulated prostaglandin (PG) synthesis, and, in fact, selenate significantly inhibited PG production. Finally, only sodium molybdate- and vanadium-containing compounds appeared to increase follicular adenosine 3',5'-cyclic monophosphate content. While all oxoanions stimulated in vitro ovulation, they had differential effects on certain signal transduction pathways when tested at concentrations that stimulated in vitro ovulation. From the results, two basic groups could be delineated, one containing tungstate-, molybdate-, and vanadium-containing compounds and the other selenate and chromate. Thus the mechanism by which ovulation is induced by chromate and selenate may be different from that of vanadium-containing compounds, molybdate, and tungstate.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals FTIR-SPECTROSCOPIC INVESTIGATION OF SODIUM TUNGSTATE AND SODIUM MOLYBDATE SOLUTIONS IN WIDE RANGE OF рH

2017 ◽  
Vol 60 (1) ◽  
pp. 56
Author(s):  
Yulya V. Matveichuk
Keyword(s):  
Ir Spectroscopy ◽  
Spectroscopic Investigation ◽  
Sodium Tungstate ◽  
Sodium Molybdate ◽  
Tungsten Particle ◽  
Complex Frequency ◽  
Selective Electrode ◽  
Wide Range ◽  
Tungstate Solution ◽  
Stretching Vibrations

For citation:Matveichuk Yu.V. FTIR-spectroscopic investigation of sodium tungstate and sodium molybdate solutions in wide range of рH. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 1. P. 56-63. A FTIR spectroscopic study of aqueous solutions of sodium tungstate and molybdate (solution concentration was 0.1 mol/l) over a wide pH range (factor (level) of acidity Z, Z = C (H+)/C (WO42-) or Z = C (H+)/C(MoO42-)) was carried out. In solutions of sodium tungstate complex frequency band at 885-865 cm-1 correspoding to the stretching vibrations ν(W-O-W) was fixed. The frequency bands of 1720-1700 cm-1, 990, 985 and 1025 cm-1 corresponding to bending vibrations δ(W-OH) were fixed that indicates a significant change in composition of the solution as a result of hydrolytic and polycondensation processes. The sodium molybdate solution has not bands corresponding to the stretching vibrations v(Mo-O-Mo). Only the characteristic bands of the deformation vibrations δ(Mo-OH) were recorded. The low intensity complex band in the area of 885-865 cm-1 corresponding to the stretching vibrations ν(W-O-W) even for freshly prepared 0.1 mol/l sodium tungstate solution was appeared as well as the band at 1720-1700 cm-1 attributed to deformation vibrations δ(W-OH) that indicates a fast change in the solution composition. For solutions of sodium molybdate bands of stretching vibrations v(Mo-O-Mo) are fixed at a pH less than 6 after standing for several days. With Hydra/Medusa program diagrams of distribution of molybdate and tungsten particle depending on the pH were calculated. In relatively dilute solutions, the diagrams received with Hydra/Medusa program showed the only protonated (monomeric) form of molybdate ions, where as in the sodium tungstate solution until pH of 9 W6O216- and HW6O215- particles exist that agrees with the results of IR spectroscopy. The results of IR spectroscopy and modeling with Hydra/Medusa program will be used to support the pH operating range for molybdate and tungstate-selective electrodes, since they are an important feature of any analytical ion-selective electrodes. For tungstate-selective electrode it is necessary to maintain the pH less than 9, for molybdate-selective electrode - less than 8 (with dilute ammonia). Considering the changes in the composition of sodium molybdate and tungstate solutions, for the design of molybdate and tungstate-selective electrodes the freshly prepared solutions have to be only used, rather than stored for more than two days.

Nuclear Magnetic Resonance and Quadrupole Coupling in Hydrous and Anhydrous Sodium Molybdate and Sodium Tungstate Spinel

1972 ◽  
Vol 50 (6) ◽  
pp. 567-572 ◽  
Author(s):  
G. F. Lynch ◽  
S. L. Segel
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Sodium Tungstate ◽  
Sodium Molybdate ◽  
Tone Burst ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Order Effects ◽  
Nuclear Magnetic

The nuclear magnetic resonance of 23Na in powder samples of hydrous and anhydrous sodium molybdate and sodium tungstate has been investigated. The anhydrous compounds crystallize in the cubic spinel of type H11, Fd3m presumably with ionic charges of 1 + and 6 + on the metals. The 23Na quadrupole couplings are the largest yet observed for this nucleus and have values of 2.62 and 2.48 MHz in the molybdate and tungstate respectively, as determined from both first- and second-order effects on the magnetic resonance spectrum. These couplings have negligible temperature dependences. Using charges of 1 + and 6 + for the metal ions, assuming that the oxygens are in their ideal positions in the spinel structure and neglecting any contributions from oxygen dipoles and quadrupoles, the electric field gradient was calculated to be 12 × 1013 e.s.u./cm3, in good agreement with the experimental gradient of 7.5 × 1013 e.s.u./cm3. Preliminary measurements of the sodium spin–lattice relaxation time, using tone-burst techniques, indicated a value between 30–60 s. The 95.97Mo nuclear resonances were also observed in the molybdate and these resonances showed no quadrupole effects.

THE EFFECTS OF MOLYBATE, TUNGSTATE AND lxd ON ALDEHYDE OXIDASE AND XANTHINE DEHYDROGENASE IN DROSOPHILA MELANOGASTER

1981 ◽  
Vol 23 (4) ◽  
pp. 597-609 ◽  
Author(s):  
M. M. Bentley ◽  
J. H. Williamson ◽  
M. J. Oliver
Keyword(s):  
Drosophila Melanogaster ◽  
Sodium Tungstate ◽  
Enzyme System ◽  
Sodium Molybdate ◽  
Aldehyde Oxidase ◽  
Xanthine Dehydrogenase ◽  
Dietary Sodium ◽  
Screening Procedure ◽  
Eye Color

The effects of dietary sodium molybdate and sodium tungstate on eye color and aldehyde oxidase and xanthine dehydrogenase activities have been determined in Drosophila melanogaster. Dietary sodium tungstate administration has been used as a screening procedure to identify two new lxd alleles. Tungstate administration results in increased frequencies of "brown-eyed" flies in lxd stocks and a coordinate decrease in AO and XDH activities in all genotypes tested. The two new lxd alleles affect AO and XDH in a qualitatively but not quantitatively similar fashion to the original lxd allele. AO and XDH activity and AO-CRM levels appear much more sensitive to mutational perturbations of this gene-enzyme system than do XDH-CRM levels in the genotypes tested.

The Synthesis of Diphenyl Carbonate from Dimethyl Carbonate and Phenol over Modified Organotin Catalysts

2011 ◽  
Vol 233-235 ◽  
pp. 124-127 ◽  
Author(s):  
Kun Mei Su ◽  
Zhen Huan Li ◽  
Ming Ding ◽  
Xiao Long He
Keyword(s):  
High Activity ◽  
Dimethyl Carbonate ◽  
Sodium Tungstate ◽  
Sodium Molybdate ◽  
Diphenyl Carbonate ◽  
Sodium Vanadate

Organotin catalysts were modified with sodium molybdate, sodium tungstate and sodium vanadate, and the modified organotin catalysts displayed high activity in transesterification of dimethyl carbonate (DMC) with phenol into diphenyl carbonate (DPC).

Effect of sodium molybdate and sodium tungstate in concrete rebar corrosion

2019 ◽  
Vol 66 (3) ◽  
pp. 253-263 ◽  
Author(s):  
Altaf Ahmad ◽  
Ranveer Kumar ◽  
Anil Kumar
Keyword(s):  
Sodium Tungstate ◽  
Sodium Molybdate ◽  
Corrosion Current ◽  
Open Circuit ◽  
Simple Method ◽  
Efficient Inhibitor ◽  
Content Type ◽  
Adverse Conditions ◽  
Cent Sodium ◽  
Rebar Corrosion

Purpose This paper aims to identify an inhibitor to protect rebar corrosion in concrete. Design/methodology/approach The authors use the simple method of polarization and calculate the change in open-circuit potential and corrosion current density. Findings Sodium molybdate is an efficient inhibitor compared with sodium tungstate for rebar corrosion in concrete. Research limitations/implications This paper has limitation of 0.0001 M concentration of inhibitors for 400 days of exposure in 3.5 per cent sodium chloride solution. Originality/value The research focused on the concentration of both inhibitors in the range from 0.1 to 0.0001 M, which resulted in greater structural protection from corrosion in adverse conditions, such as coastal areas.

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